Char is made by heating a cellulosic material in a low oxygen environment at a temperature of between 600-700° C., with higher temperatures unnecessary for current processing needs. This process typically takes between 12-72 hours, though longer periods are possible, and the process burns off volatile compounds such as water, methane, hydrogen, and tar. In commercial processing, the burning takes place in large concrete or steel silos with very little oxygen, and the burning stops before the material turns to ash. The process leaves black lumps and powder, about 25% of the original weight.
Historically, char referred to charcoal, which was used for cooking and heating. The process of making charcoal is ancient, with archaeological evidence of charcoal production going back about 30,000 years. Making charcoal is modernly practiced throughout the world. Indeed, individuals utilize cellulosic matter, which is burned or charred at low oxygen conditions, to generate charcoal. When ignited, the carbon in charcoal combines with oxygen and forms carbon dioxide, carbon monoxide, water, other gases, and significant quantities of energy. The quantity of energy is the salient feature as charcoal packs more potential energy per ounce than raw wood. Furthermore, charcoal burns steady, hot, and produces less smoke and fewer dangerous vapors. Because charcoal burns hotter, cleaner, and more evenly than wood, it was used by smelters for melting iron ore in blast furnaces, and blacksmiths who formed and shaped steel, among other uses.
Many societies around the world use charcoal for cooking and heating purposes when no other heat sources are readily available. Even in modern metropolises, hardwood lump charcoal is fashionable for the same reasons that “organic” food is fashionable, and it has obtained an aura of being more natural, has increased flavor, and is a better way to cook. There are more than 75 brands of charcoal and some are even varietal including: cherry, mesquite, coconut shell, tamarind, etc. Each of these varietals are essentially identical, except for their plant origins and traces of oils defining their unique scents and raw source material.
Hardwood lump charcoal is frequently made from hardwood scrap from sawmills and from flooring, furniture, and building materials manufacturers. However, absent such scrap material, sources often include branches, twigs, blocks, trim, and other scraps for generating the material. The result of such variety of material is lumps that are irregular in size, often looking like limbs and lumber. Often, this material is carbonized to different degrees because the different sized lumps lead to slight differences in burn and temperature among the materials. Lump is particularly valued for cooking as it leaves little ash since there are no binders as with manufactured charcoal, thus leaving a cleaner product than manufactured charcoal, and supposedly provides natural flavors for cooking. Certain charcoals contain additional fillers or accelerators, to aid in combustion, while others, e.g. binchotan, burn at much higher temperatures due to its particular processing.
Interestingly, as wood and other cellulosic materials are carbonized, the material structurally changes into simple carbon structures. This has been historically utilized for its absorptive properties, for example in filtering wastewater as well as binding body toxins. Large amounts of carbon are utilized for these purposes in numerous industries. Furthermore, in certain instances, these structures may store or conduct small amounts of electrical charges, whereas non-carbonized cellulosic material does not conduct electricity. However, little, if any, carbonized material is currently used for such electrical property, as these materials still fall below transmission rates for classically transmitting materials for transmitting electrical charges or storing electrical charges, such as metallic based materials.
Carbon products based on hemp have heretofore been neglected. This neglect is due to numerous reasons including the significant difficulties with the plant's mechanical structure, generation of sticky resin substances on the stalk during retting, its light mass and density, and presence of certain metabolites and cannabinoids, which have generally precluded its use. The processes and methods described herein advantageously provide new methods and processes to generate micron-sized particles from hemp-based cellulosic materials, which are advantageously utilized in masterbatches for certain industrial processes, including fiber formation, film formation, and composite formation, among other uses.